A novel Smith predictor with double-controller structure

Aiming at the disadvantage of the conventional Smith predictor with weak robustness, a novel one with double-controller is proposed in this paper. It has a two-degree of freedom structure so that the setpoint response is decoupled from the disturbance response. Thus, the setpoint tracking and disturbance attenuation controllers can be designed separately. At the same time, the two controllers are all designed into PID structures whose parameters can be adjusted by a parameter, respectively, so that the corresponding response tends to be optimal.